1. Field of the Invention
The present invention relates generally to the field of internal combustion engine injection systems. More particularly, the invention relates to a technique for controlling fluid flow and spray characteristics of a spray assembly by providing a flow enhancement assembly near the exit of an outwardly opening poppet.
2. Description of the Related Art
In fuel-injected engines, it is generally considered desirable that each injector delivers approximately the same quantity of fuel in approximately the same temporal relationship to the engine for proper operation. It is also well known that the fuel-air mixture affects the combustion process and the formation of pollutants, such as Sulfur Oxides, Nitrogen Oxides, Hydrocarbons, and particulate matter. Although combustion engines utilize a variety of mixing techniques to improve the fuel-air mixture, many combustion engines rely heavily on spray assemblies to disperse fuel throughout a combustion chamber. These spray assemblies may produce a variety of spray patterns, such as a hollow or solid conical spray pattern, which affect the overall fuel-air mixture in the combustion chamber. It is generally desirable to provide a uniform fuel-air mixture to optimize the combustion process and to eliminate pollutants. However, conventional combustion engines continue to operate inefficiently and produce pollutants due to poor fuel-air mixing in the combustion chamber.
Accordingly, the present technique provides various unique features to overcome the disadvantages of existing spray systems and to improve the fuel-air mixture in combustion engines. In particular, unique features are provided to enhance the fluid flow through an outwardly opening nozzle assembly to provide desired spray characteristics.
The present technique offers a design for internal combustion engines which contemplates such needs. The technique is applicable to a variety of fuel injection systems, and is particularly well suited to pressure pulsed designs, in which fuel is pressurized for injection into a combustion chamber by a reciprocating electric motor and pump. However, other injection system types may benefit from the technique described herein, including those in which fuel and air are admitted into a combustion chamber in mixture. Accordingly, a technique is provided for enhancing fluid flow in an outwardly opening nozzle assembly. A flow enhancement assembly is provided adjacent an exit from an outwardly opening poppet to provide desired spray characteristics. The flow enhancement assembly includes converging and diverging passages and a plurality of ports to form a spray.
In one aspect, the present technique provides a nozzle comprising an outwardly opening poppet disposed in a conduit and a spray formation assembly disposed adjacent a forward portion of the conduit. The outwardly opening poppet includes a fluid passage section and a head section removably seated against the forward portion. The spray formation assembly includes a flow enhancement passage comprising a contracting passage and an expanding passage. The spray formation assembly also has a plurality of ports coupled to the flow enhancement passage.
In another aspect, the present technique provides a combustion engine comprising a combustion chamber, an ignition assembly coupled to the combustion chamber, a spray assembly coupled to the combustion chamber, and a fuel delivery assembly coupled to the spray assembly. The spray assembly includes an outwardly opening flow controller disposed in a conduit and a forward flow assembly disposed adjacent the outwardly opening flow controller. In this embodiment, the forward flow assembly has converging and diverging passages.
In another aspect, the present technique provides a method for forming a spray from an outwardly opening nozzle assembly. The method comprises passing fluid through a flow enhancement assembly forward an outwardly opening poppet disposed in a fluid conduit. The flow enhancement assembly includes converging and diverging passages having a ring-shaped cross-section. The method also comprises passing the fluid through a plurality of ports coupled to the flow enhancement assembly.